[password autofill] Add serialization for FormData and FormFieldData

components/autofill/core/common/form_data.h

Index: components/autofill/core/common/form_data.h
diff --git a/components/autofill/core/common/form_data.h b/components/autofill/core/common/form_data.h
index 202fb8d3f95906782e281d858c5b1c66385ee6ee..1d6dffae2d8aa578f62d08c852c332263c816b4c 100644
--- a/components/autofill/core/common/form_data.h
+++ b/components/autofill/core/common/form_data.h
@@ -37,6 +37,13 @@ struct FormData {
   std::vector<FormFieldData> fields;
 };
 
+// Serialize FormData. Used by the PasswordManager to persist FormData
+// pertaining to password forms. Serialized data is appended to |pickle|
+void SerializeFormData(const FormData& form_data, Pickle* pickle);
+// Deserialize FormData. This assumes that |iter| is currently pointing to
+// the part of a pickle created by SerializeFormData. Returns true on success.
+bool DeserializeFormData(PickleIterator* iter, FormData* form_data);
+
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_COMMON_FORM_DATA_H__